High voltage, high current semiconductor switching devices are known. One such device is the insulated gate bipolar transistor (IGBT). IGBTs usually employ a large number of spaced cells, which may be rectangular or hexagonal cells, or may be parallel stripes in planar or trench topology. Base current control in such devices is not possible; the devices may have a relatively high forward voltage drop; and the conventional IGBT has a current tail during turn off.